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Thermal resistance values for Cyclone III devices are provided for a boardmeeting JEDEC specifications and for a typical board. The JEDEC boardspecifications require two signals and two power/ground planes and areavailable at jedec.org The values are described in Tables 1through 4.
Table 1. Thermal Resistance Values for Cyclone III DevicesValue DescriptionθJA (C/W) Still Air Junction-to-ambient thermal resistance (θJA) with noairflow when a heat sink is not being used.θJA (C/W) 100ft./minuteJunction-to-ambient thermal resistance with 100ft./minute airflow when a heat sink is not being used.θJA (C/W) 200ft./minuteJunction-to-ambient thermal resistance with 200ft./minute airflow when a heat sink is not being used.θJA (C/W) 400ft./minuteJunction-to-ambient thermal resistance with 400ft./minute airflow when a heat sink is not being used.θJC (C/W) Junction-to-case thermal resistance (θJC) for device.θJB (C/W) Junction-to-board thermal resistance (θJB) for specificboard being used.
